1. Field of the Invention
The present invention relates to an axial turbine, such as a steam turbine or a gas turbine.
2. Description of the Related Art
In the axial turbine, the stationary blades increase the velocity of a working fluid and deflect the working fluid in the rotational direction of turbine rotor. The working fluid with the rotational velocity components provides kinetic energy to moving blades and rotates the turbine. In order to induce such a flow of the working fluid for driving the turbine rotor, the height of the outlet flow path of a turbine stage measured in the radial direction of the turbine rotor is made higher than the height of the inlet flow path of the turbine stage, in conformance to the fact that the inlet of the turbine stage is higher in pressure than the outlet thereof. As a result, generally, on a stationary blade annular plane outer periphery in each stage, the flow path height monotonically increases from the inlet toward the outlet of the stage (refer to JP, A 2003-27901 for example).